Why alpine lakes?¶
You may be wondering why alpine lake chemistry is so important. These lakes are at high elevations! Some are very small, and tucked away in basins not easily accessible. It's true these lakes are remote, but they are vital water sources. Alpine lakes feed the streams that become tributaries to major rivers, which serve as cruicial water resources for the communities of the intermountain west. Alpine lakes are the ultimate headwaters for western watersheds, and changes in lake chemistry are known to propegate downslope and downstream. These lakes serve as sources and buffers for mountain streams - they store ions and neutralize acids, which helps regulate pH and nutrient abundance (nitrates and phosphates are important in nutrient-limited systems, but an over-abundance can result in oxygen depletion and other cascading environmental effects).$^{[1]}$
The communities that depend on these vulnerable water sources are growing, and with that growth comes increases in anthropogenic emissions - we are releasing more nitrates, phosphates, and sulfates to the atmosphere via industry and agriculture.$^{[1]}$ These compounds end up in lakes and soils via atmospheric deposition, and ultimately end up in other parts of watershed ecosystems via the hydrologic cycle. We need to understand how water chemistry is changing in alpine lakes so that we can inform water resource management decisions, and more effectively prioritize long-term water quality and sustainability.
Figure 3: A simplified diagram describing atmospheric cycling of nutrients, and atmospheric deposition. Atmospheric deposition is part of a natural cycle of nutrient exchange, but anthropogenic emissions introduce an impbalance in the cycle, resulting in more of these compounds concentrating in lakes via acid precipitation. Image from the USFS Air Resource Management Program.
Figure 1 image adapted from the USFS RMRS Ecoregions page.
